1. Field of the Invention
The subject invention relates generally to communication systems and more particularly to a method for encoding speech which faithfully reproduces the entire input signal including the speech and attendant noise.
2. Description of Related Art
In speech coding, the input signal can be either clean or have additive acoustical background noise. The latter has become more and more common as the use of cellular phones has increased. It is commonly known that todays lower-rate (&lt;12 kbit/s) speech coders handle the background noise conditions inadequately. The problem is that the algorithms designed for speech coding are highly specialized for speech, and handle other input signals (e.g. acoustical noise) poorly due to a significant difference in the statistics of the signals and the perceptually important aspects of the signals.
In an effort to combat this problem, persons in the art have resorted to adjusting the speech coding algorithm to better accommodate the background noise without sacrificing the speech quality too much. Other proposed solutions make use of noise suppression on the input signal before the encoding. This approach however is unable to faithfully reproduce the original input signal. Several cellular phone standards apply the approach of noise suppression.